1. Field of the Invention
The present invention relates to a technology of an electrical connector, particularly, to a mechanism to connect a flexible circuit board to a connector.
2. Description of the Related Art
A flexible circuit board is comprised of a flexible board, wirings provided on the flexible board and connection pads to be conductive through wirings, which are provided on the edge of the flexible board. When the flexible circuit board is used, it is placed onto a flat type connector, and then pressed and held, so that the connection pads contact with corresponding terminals of the connector. Such connection structure is known, for example, by disclosures in Japanese Unexamined Patent Publications Nos. 8-255961, 8-227745 and 3-182075.
In this type of connectors, the flexible circuit board or the connector has a flat connecting section (e.g. connection pad), and the other, the one between the flexible board and the connector which does not have the flat connect section, has a protruding elastic contact section. By putting in place and then pressing the flexible circuit board and the connector, such that the protruding elastic contact section is pressed to/into the flat contact section, the connection between the flexible circuit board and the connector is achieved and maintained. Therefore, the connection is achieved without an inserting force for engagement, such as the one required for the connection of terminals of normal connector. Also, since the terminals are arranged in columns and rows in those methods, the contact points to prevent the inserting force from becoming too large.
In such publicly known devices, a pressuring member is used to press the flexible circuit board towards the connector. According to the mechanism of the pressuring member, it is difficult to press the whole area of the connecting section of the flexible circuit board by the pressuring member to connect with the connector. Therefore, the pressuring member merely presses locally, for example, on both edges.
Since the flexible circuit board is flexible itself, it causes a distortion, such as deflection or torsion, if it is locally pressed. In other words, the connecting pressure is not uniformly applied to an area of the connecting section, which causes poor connection or the like, so that its electrical properties become unstable. Those problems are more conspicuously observed for flexible circuit boards having a large number of connection pads (contact points).
Accordingly, it is an object of the present invention to provide a structure for the connection of the flexible circuit board, which enables uniform and stable connection without such problems even when the flexible circuit board has a large number of contact points.
According to the present invention there is provided the flexible circuit board connecting device comprises a flat-type connector to connect with a specified circuit member and a flexible circuit board to connect with the circuit member via the connector.
In the flexible circuit board connecting device according to the present invention, the connector holds a plurality of terminals in holding holes of a housing, and each terminal has a connecting section on one side of the housing to connect with a circuit board and a contact section on the other side to contact with the flexible circuit board. The contact section between flexible circuit and the terminal can move opposing each other in a direction parallel to the surface of the flexible circuit board from specified zero inserting force position, where the flexible circuit board and the connector are contacted over the surface by zero inserting force, to a contact position, where the flexible circuit board and the connector are contacted under elastic pressure.
According to the present invention, the flexible circuit board is brought to a position, where its contact portion is close to the contact position of the corresponding terminal, by zero inserting force, and then moved in a direction of the surface, so that the contact portion comes to contact with the contact section under an elastic pressure. Each contact portion and its corresponding contact section simultaneously contact under the same condition, so that all the contact portions and their corresponding sections can evenly be contacted without uneven contact due to the flexibility of the flexible circuit board.
In an embodiment of the present invention, the device is made as follows. The contact section of the connector is formed on an elastic arm, which protrudes from the other side of the housing and extends along the surface. A window is provided to the housing for receiving the elastic arm at the zero inserting force position, and a connection pad is provided near the window. The contact portion is contacted with the connection pad under an elastic pressure at the time of relative movement towards the contact position.
In this case, the terminal of the connector is made to have another arm to tightly press the flexible circuit board by moving in concert with the elastic arm. By doing this, the contact between the flexible circuit board and the connector is further ensured. In this embodiment, the connecting pad and the window of the flexible circuit board and their corresponding terminals are arranged in columns and rows so that the number of the contact points can be increased.
In another embodiment of the present invention, the flexible circuit board is made as follows. The flexible circuit board has a contact pin to connect with the terminal of the connector, which is provided so as to protrude from the surface of the flexible circuit board towards the connector. The contact pin is put into the holding hole of the connector at the zero inserting force position, and contacts with the contact section of the terminal under an elastic pressure through the movement of the flexible circuit board towards the contact position.
In this case, the terminal of the connector is made such that the contact section tightly presses the contact pin so that the contact can be further ensured. Even in this embodiment, each contact pin of the flexible circuit board and its corresponding terminal of the connector are arranged in columns and in rows, so that the number of the contact points can be increased. The embodiments of the present invention are described below, particularly referring to the accompanying figures, FIGS. 1 through 4.